This invention relates to roofing roll products and to a method and apparatus for making the same. It relates particularly to the use of chips or flakes of the type produced according to the method and apparatus disclosed in U.S. Pat. No. 4,215,084 applied to a bitumen substrate. The chips described in this patent are uniform in size and in the range of 20 to 30 mills square by 1 to 2 mills thick. However, the particle sizes could be larger or smaller but preferably rectangular in shape.
The present invention relates to the application of such chips, particularly aluminum chips, to a suitable base preferably in the form of a sheet or membrane coated with roofing asphalt or other bitumen material. The chips are applied uniformly in flat contiguous covering relationship so that they will shield the membrane from ultraviolet rays that oxidize and polymerize the roofing asphalt. The chips have a tough mirror-like finish which results in substantially increased solar reflectance as compared to conventional aluminum-asphalt roofing of the granular top surface type.
In the past, various methods and materials have been used in protecting the roofing base, usually in the form of a sheet or membrane, which may be reinforced or non-reinforced, and coated with asphalt or other suitable bonding material for receiving and retaining the protective material. This protective material has taken various forms in the prior art. For example, one of the most commonly used has been rock aggregate which is difficult and expensive to apply and does not have good solar reflective properties. Another conventional type used is aluminum paint which requires considerable labor to install and a waiting period to allow the base coat of asphalt to cure prior to the application of the paints and, although the resulting coating does have better reflective properties than the gravel, it is not the most effective to reduce internal building heat created via solar energy. In U.S. Pat. Nos. 2,133,988 and 2,332,219 a method has been proposed to increase the protection of an asphalt roofing membrane by applying a substantially continuous layer of finely divided aluminum flakes and then applying granular particles, such as crushed slag or pebbles, with sufficient force to slightly displace the aluminum particles so as to penetrate the layer of such particles and to become embedded in the asphalt. This process is also difficult and time-consuming to perform and the granular particles of the resulting coating detract from the solar resistance and reflective capabilities of the aluminum flake layer.